I will need one 5.25" slot, two 3.5" slots and clearance for a normal-length GPU. Would prefer an all-metal finish if possible. The Silverstone Sugo SG101B
comes closest to what I'm looking for.
External 3.5", or you just mean for internal drives? If you need external, that's a little trickier. So far, Silverstone and Lian-Li have been among my favorites for brands, and between the two there's some good variety in any given form factor.
I have the Lian-Li PC-354A, but the whole line appears to now be discontinued judging by them all being out of stock at newegg. Still, I can recommend the case. It's a little wider than your average case, sticking the PSU off to the side instead of above/below the mobo. This cuts down the height significantly (which was important for me). It has one stealthed DVD drive bay, and the internal layout is very flexible for either super-long GPUs or bunches of 3.5" drives.
Something a little more standard, but I'd have seriously considered if it was released at the time, is the Silverstone TJ08-e (http://www.newegg.com/Product/Product.a ... 6811163182
But as you've observed, few of these are highly compact. I admit these days my tastes are leaning more mITX. If you're looking at the SG01, you might consider the mITX options. (Frankly, I'm largely disappointed, but there are still a few good options out there.)