Originally Posted by redorchestra
Can an internal hub gear be fitted with a cassette to give that granny gear, and a higher cruising speed?
I can't answer your other questions, but I do know there are ways to get that granny gear.
1- With a Schlumpf
mountain shifter (expensive, in my opinion). This will reduce your bottom gear by 40%.
2- Put in a smaller ring upfront, such as a triple MTB crankset (to do this, you may need to lengthen your chain and change the front derailleur; also, your rear derailleur may not be able to handle a longer chain)
3- Change the cassette from 14x28 to 11x32, or even 11x34, if your rear derailleur can handle all the chain slack (if not, you may need to change it to a long cage variety, which may put it too close to the ground)
4- Less expensive than the Schlumpf mountain drive would be a SRAM 3x9 (it's a 3 speed internal gear hub with a 9 speed derailleur). Depending on the spacing of your rear dropouts, you may need to expand your frame a little. Sheldon Brown has some excellent information on frame spacing