Best dry fly for me last year was foam-backed Convertible (check out Fly Of the Week 3rd quarter 2005). Only difference I made was to add a strip of 2mm foam (try and match color of dubbing as close as possible). The fly was unsinkable, even after taking a number of fish - it did great job as an indicator, too. No reason you couldn't mod a Stimulator, too - Charlie Craven has one of these on his website (http://www.charliesflyboxinc.com/flybox)

Regards,
ScottP