I've been making UDS's for several years now...I've made over 20 of them and I've always used "food grade" barrels from a local bakery cause that way I know what has been in them and that they are lined.
When I get them, I cook the liner out, then have them sandblasted inside and out.
It may take a little more work, but I would rather start out with a "food grade" barrel with a liner than go with a "reconditioned raw" barrel and wonder what has been stored in that barrel previously...
That's my 2¢
Shawn aka: BUBBA's QUE CREW Competition Team
Blue Weber Performer w/SS top & gas assist
Weber One Touch Gold & a Weber 22 1/2" Silver
2 UDS's Born 9-19-08 & 3-6-09
Weber Smokey Joe Platinum
Super Fast RED THERMAPEN
"If you got them by the MOINK balls, their hearts and minds will follow" -John Wayne