the Catalinbread Dirtly Little Secret works beautifully for this purpose.
The DLS does the Marshall in a Box thing really well, and the Superbass setting on the newer mkiii version of the pedal was basically designed so that you can stack fuzz into it and sound convincingly killer without the need for a marshall stack.
Strat -> Fuzz of your choice -> DLS mkiii set to Superbass -> clean amp (fender-style preferably) = AWESOME.
I've tried a ton of fuzz pedals, and a good fuzz face used like this will get you Hendrix tones all day long. great ones, too.