For diesel engines specifically.
Here's a huge thread listing members with failures at TDIclub forum:
http://forums.tdiclub.com/showthread.php?t=293629
Failure list as taken from the forum and you can see it's rather significant!
Alabama 4
gprim AL 2010
patdavid AL 2011
speedeep AL 2011
Redwave92 AL 2009
Arizona 6
2009TDINEWBIE AZ 2009 first failure
2009TDINEWBIE AZ 2009 second failure
WL-ShroderGTI AZ 2009
Plus3Golfer AZ 2009
AZ-TDI AZ 2009
LazerBlueBeast AZ 2009
Arkansas 2
zoeygirl AR 2011
jchall101 AR 2009
California 59
NipomoTDI CA 2010
chadjaeger CA 2009
rjgaliano CA 2009
gborgan CA 2009
hocking CA 2009
astaal CA 2009
lovehatevw CA 2009
phathead CA 2009
proulx70 CA 2009
durundal CA 2009
funkychicken81 CA 2010
smokeskleen CA 2010
pjcan CA 2010
Phancey CA 2009
dr.freud CA 2009
SFOPilot CA 2011
JohnAlt CA 2009
chummer CA 2010
danix CA 2010
SandDiesel CA 2009
gotconsultants CA 2009
elbrowno CA 2010
Mark Jeffreys CA 2011
Screenial CA 2009
idea man CA 2010
marleyi CA 2010
joseph2012 CA 2010
fireinsyrup CA 2011
AJALE CA 2010
rinsco CA 2009
Seeuarndjimmy CA 2009
bort CA 2011
zaus60 CA 2009
Zaius CA 2009
potiron CA 2009
ne31097 CA 2011
Klystron. CA. 2011
gruder18 CA 2010
istone CA 2010
cstajduhar CA 2011
todd4218 CA 2011
rinsco CA 2009
specialagentdale CA 2010 first failure
specialagentdale CA 2010 second failure
tdi10sb CA 2010
plus1 CA 2010 Q7
plus1 CA 2010 A3
MM48 CA 2011
rmchung CA 2010
tdidanny CA 2010
Fredkap CA 2010 Q7
rosaluma CA 2012 P
tobo CA 2009
macattack963 CA 2012
ocindymom CA 2009
basspfeifer CA 2011
CraziFuzzy CA 2009
yaknuts CA 2012
510Finn CA 2010
Colorado 5
ohcaptainron CO 2010
TurboKid CO 2011 first failure
TurboKid CO 2011 second failure
Thorny CO 2011
storx CO 2009
Connecticut 4
andicame CT 2010
baggsgt CT 2012
AMT1281 CT 2009
mfisel CT 2011
Florida 20
Chadmag FL 2009
tallymom FL 2009
Knowledge FL 2009
ferland25 FL 2010
jessesrq FL 2009 first failure
jessesrq FL 2009 second failure
WFLTDI FL 2009
Whodathunkit50 FL 2010
1972SS454 FL 2009
upsbroke FL 2009
batgo FL 2009
rich! FL 2011
bcarr001 FL 2010
ajkreider FL 2011
2010TDIWagen FL 2010
ErickL FL 2009
TR10 FL 2012
Data saurus FL 2011
RdPrry FL 2009 first failure
RdPrry FL 2009 second failure
Georgia 3
house-1221 GA 2009 first failure
house-1221 GA 2009 second failure
xracer111 GA 2009
Illinois 6
jedwyl IL 2010
Kennytdi IL
vonnie77 IL 2009
marc.d.taylor. il 2009
4 TUGGIN IL 2009
rpulfer IL 2009
Indiana 1
straightliner IN 2009
Kansas 1
upsbroke KS 2009
Kentucky 1
Paramedick KY 2009
Louisiana 2
Sunglassesjohnny LA 2010
GerardS LA 2009
Maine 1
subsonic44 ME 2009
Massachusetts 7
LoneWolf MA 2009
rte2MA MA 2010 first failure
rte2MA MA 2010second failure
pcnorton MA 2011 first failure
pcnorton MA 2011 second failure
emerscape MA 2011
TDIinMA MA 2011
Michigan 2
Saltlick48103 MI 2009
icebox114 MI 2010
Missouri 1
STL-JSW MO 2010
Mississippi 2
Sharpie MS 2009
xtdilover MS 2009
Maryland 1
cankicker MD 2009
N Carolina 9
tonydec NC 2009
NC Chicklady NC 2009
y0bailey NC 2009
dustingebhardt NC 2010
lindsaysuchy NC 2010
Cosmos NC 2012
Baltman195 NC 2012
New Hampshire 1
Nickofari NH 2009
Nevada
New Jersey 8
asrnj77 NJ 2009
rcann NJ 2010
Diesel Wiesel NJ 2009
N2UADTDI NJ 2009
The_Mike NJ 2011
gregert12 NJ 2010
tdiregrets NJ 2009
JCTDI NJ 2009
New Mexico 1
VWJim NM 2011
New York 13
birkie NY 2009
swb1509 NY 2010
TDIFirstTimer NY 2010
Sunberg2 NY 2009
saaronson NY 2010
peterf NY 2009
Jack Sprocket NY 2010
vwmj NY 2009
fred1331 NY 2010
lcjjm4 NY 2010
rickdiculous NY 2010
Susang NY 2010
Colonel A NY 2009
Ohio 3
rickchip OH 2009
steelyeyed OH 2009
TooTall OH 2010
Oklahoma 2
freeman OK 2009
mandy1105 OK 2009
Oregon 3
Haz-matt OR 2009
JohnofD OR 2010
mcnzder OR 2010
mdgreven OR 2011
Pennsylvania 5
Kthackst PA 2010
Absolute Diesel PA 2010
amy1000 PA 2010 first failure
amy1000 PA 2010 second failure
kndonlee PA 2010
Rhode Island 2
tdisky RI 2009
pjcam5 RI 2011
South Carolina 2
Godstang SC. 2012
Wesleybyars SC 2009
Tenneesse 5
MonicaC TN 2010
TDI117 TN 2012
bigmacd TN 2011
tempokat TN 2011
Dave@swamps TN 2011
Texas 25
Maverick395 TX 2009 first failure
Maverick395 TX 2009 second failure
jshoutex TX 2009
catnip TX 2010
Kevin 73 TX 2011
Houston2010tdi TX 2010
carrolltoncorrado TX 2009
PlanoWagen TX 2009
ffdfrontman TX 2010
drckol TX 2009
dickey TX 2010
Tim2112 TX 2009
T Girl TX 2011
TXANN TX 2012
doug67coug TX 2009
tdininja TX 2009
giavid TX 2010
quietTDI TX 2009
JonD-2.7tDallas TX 2011
EasyT TX 2011
Moralesj TX 2011
spanish11 TX 2011
jlockhart TX 2010
tuan209 TX 2009
HozzMidnight TX 2009
Utah 3
53 willys UT 2010
RoccoRcr UT 2011
s3j UT 2009
Vermont 1
Colonel A VT 2009
Virginia 9
O2Waster VA 2009
elester12 VA 2009 first failure
elester12 VA 2009 second failure
freakMike3 VA 2009
jsds VA 2009
talbottw VA 2009
Matt Man VA 2009
BlkJetta01 VA 2009
TDITIM60 VA 2010
Washington 3
planger WA 2011
xenoice WA 2012
tdi one ton WA 2011 pending
West Virginia 3
dweisel WV 2009 Jetta Sedan
dweisel WV 2009 JSW
SCWC_WV WV 2009
Wisconsin 3
spjetta WI 2009
I love my Jetta WI 2010
sickmtbnutcase WI 2009
Canada 7
stylinmama CANADA
Heavyfuel QC CANADA 2009
BrokenTDI BC CANADA 2010
r2k QC CANADA 2010
saltspringtdi BC 2010
Cristian ON 2010
VWascension ON. 2009
State info not available 7
mystreva 2009
Chris & Theresa XXXXXX double failure
Chris & Theresa
RLS1400 2009
Kiwanda 2009
Absolute Diesel 2010
Adrenalinaddict 2010