Jermarcus Ricks is the only true DT we are after right now. Motley, if he goes to the D-line, will need to put on about 20 lbs or so.
Michael Goggans will likely grow into a DT after starting out at end. He needs to put on a bit of weight, but has the frame.
I don't know if we'll see another Anthony Bryant DT any time soon, but Byron Walton is a big boy.
Our next DT's will likely be Washington, Walton, and maybe Fanney. All are/will be in that 280-290 range and a little more lean. Which is fine b/c the are more agile and will usually play at a good pad level. Walton will play around 300.