I'm trolling for opinions on the best ways to load prep samples (20 - 1000 mg) on RP columns, usually running MeCN/water. I've tried methanol, 50-50 MeCN/water with a dash of methanol for solubility, and straight DMSO with a 5 min 98% water wash before the gradient starts. The DMSO method seems to work better and is more general, but I was wondering if there were any other tricks out there. The samples consist of a wide variety of small molecules from our med chem group and little or no method development can be done before hand, so the more general the method the better.

You've already got it!! DMSO works great for what you're doing. Stay away from the non-polar solvents like THF. If Methanol is used for solubility, why isn't it used in the mobile phase?

There are other tricks! We just wrote one up for a publication in Advances in Chromatography. Dissolve your sample in DMSO, set up your system to pump the DMSO sample onto the column in a stream of 100% MeCN that is diluted just before the column with water to get you to the starting composition of your gradient, for example 5% or 10 % MeCN. You get significantly higher loads onto the column than with any other approach.
Uwe Neue