bupkus,
Sure,..........there are many good cases and hsf's to choose from that seem to fit your criteria, I will start off the suggestions and hope that others will post and give you some second opinions.....................?
1) The 600 Duron sounds like the value choice king (last one I priced locally -so no shipping charge- was $55.-OEM version).
2) I'm not sure about the Palomino,........... but the price of the Athlons up to 1GHz. is getting lower all the time.
Cases,..........................the first one that comes to mind is the
Fong-Kai 603, not too big, but big enough,....... has excellent cooling characteristics w/no modifying really necessary and great quality for the price. (choice of two front covers, so it doesn't look empty w/just one drive bay filled.....and I am told the plastic side covers are quieter than the metal ones)?
The MSI K7TPro-2A sounds like a rock solid, budget choice, can't go wrong with all the accolades from AnandTech reviews and other MSI users.
(I have no personal experience w/MSI but would try one myself for the price!)
For HSF's I like the GlobalWin FOP32-1 for $20., if the fan is too loud for you just replace w/quieter one,.............if not enough cooling, just replace fan w/high speed one (you don't have to remove hs from cpu to replace the fan, just release two wire spring clips).
I have a Taisol CGK742092 on order - $17.95 + shipping, can't comment on it yet, but according to other posts, it has to be modified (filed down) in order to fit the MSI K7T.