Middle-range Macs

I'm looking for a desktop Mac.

I'm pretty unhappy with the current Apple offering. We have the high-end Mac Pro, starting at 2.499€ (but you can configure a single CPU version for 2.049€, and at the low end, the Mac mini, starting at 499€. In the middle we have the iMac's but those have a built-in screen, and I already have dual 20" Wide displays that I would like to reuse.

I wonder if Apple will ever fill the void between the two head-less versions they have now. I want multiple internal disk-drives (or at least an eSATA connector) because for my main workstation I like to have RAID1, but the only way to get those is a Mac Pro, way to expensive.

There are alternatives, but I would like to avoid the hassle.