The schlumph mountain drive bottom bracket with planetary gears looks pretty cool. It is foot actuated and allows a reduction of 2.5. I was curious what sort of gears it would give my bike so I calculated:

front gear	rear gear	gear inches
1	1	18.6
1	2	25.5
1	3	34.6
2	1	44.6
2	2	61.1
2	3	83.1

No wasted gears, a nice shifting pattern with only one double shift, as low a gear as I could want for a really steep hill or a really heavy trailer. A total range of 501%, which is almost as good as a rolholff's 526%. The schlumpf is rated for use with coaster brakes, and my SRAM T3 is tough enough for the schlumpf. But how to justify $.5K for a new bottom bracket?

For reference, my current gearing is based on approximately 28 inch wheels (622mm rims, largeish tires), a 48 tooth front cog, a 22 tooth rear cog, and a SRAM T3 hub that offers 1st, 2nd, and 3rd at 73%, 100%, and 176%.