Agreed, I think the most difficult thing with a midi UDS is actually finding a 30-35 gallon drum. If you can do that, I would make the midi. I really like mine and it's big enough to smoke a turkey. I smoked a 14 pound bird on it for Christmas. I have 3 rack positions. One just over the charcoal basket for a diffuser (or a 1/4 roasting pan to catch drippings). Then a rack in the middle and one just below the top. I have a 18 inch kettle lid as the top.
For the charcoal basket, I wrapped expanded metal around a 18 inch weber charcoal grate.
I have seen 30 gallon drums with Mobil 1 logo's at my local oil change place...may be a good place to check? Buying a new one is expensive.
Battle Box - Midi UDS - Weber Performer - 22.5 Weber OTG - Weber Genesis - GOSM - White Lightning Thermopen