Chenbro makes some good server cases and ewiz.com sells them at good prices. Or you could look at something like the Silverstone Temjin 5 (SST-Tj05) or the Aerocool Coolview - an inexpensive stacker-style case, or you can get the real Stacker at good prices right now (after rebate) from ZZF et al. These have 10 or so 5" bays and you can add passive drive cages that hold 3 (in two or three 5" bays) or 4 HDDs (in three 5" bays) per cage or you can add Hot Swap cages that hold up to 5 HDDs per three 5" bays.
The original stacker is designed to hold 2 PSUs which can be more cost effective when running large numbers of drives than one huge PSU.
http://www.servercase.com and
http://www.buildtoorderservers.com sell server cases that aren't generally seen on mass-market consumer sites like Newegg.
And Chenming/Chieftec/and clones sell entry level server cases that can hold at least 6 HDDs. Plus having a number of free 5" bays.
Oops, I forgot the Codegen 9000 series (see dealsonic.com) and the Enermax 10182. The
10182 can hold 6 HDDs in the rack and 2 more on the arm before using any 5" bays.
.bh.