Thanks Hedy,
1) the intake on the system is non-clogging since it's a cutter pump impeller (see stancor.com sc-50) so it cuts leaves, debris as it enters the pump, which is very close to the intake. I would probably do the same--keep the pump as close to the intake as possible so that leaves are cut up without any length of tube to get caught up in like a shop vac.
2) The proskim system uses gravity--the duckweed/watermeal/leaf infested water is pumped at the floating unit and then onto an inclined screen where the duckweed rolls off onto a catch area or the ground.
I think there are a couple things I'd like to incorporate.
a) use the pump to not only skim surface weeds, but optionally attach the intake to a hose to pull it off the bottom, around rocks, etc.--should be just a hose off the intake. On normal trash/effluent/cutter/seware pumps, there is no circular "inlet" to attach a hose--that is added separately. I'm sure that wouldn't be difficult. Proskim attaches a circular vortex creation to get the proper flow of surface weed into the pump.
b) when not skimming weeds, turn the intake 90 degrees downward and on the discharge side disconnect the hose to shore and in place connect a nozzle for a fountain. Should be easy. This guy builds them from a fountain pump.
http://detroit.craigslist.org/for/1233158101.htmlgranted you'd need a longer cord or just have a fountain close to shore.
The point is that one motor should be able to do all functions ideally.