SHG Model Supplies
I bought the bits from here but the web site has been "Under Construction" for months now. There is a contact e-mail posted though and there is a phone number on the Info page.
They can supply the nice little brass props for you but if you have the shafts and tubes you can make up a couple of close fitting plastic bushes yourself. You simply want a tight fit in the ends of the tube, or a smear of epoxy, and a 2mm hole drilled through the centre. Mine is filled with a light oil, anything heavier and my motors won't turn but yours should be a lot more powerfull anyway, and I've not had a leak yet.
For couplings the Robbe rubber tube type are perfect and run really smoothly. Once again your motors might be a bit too powerfull for them but leave yourself room and you could fit UV joints at a later date if you had to.
To be honest you may find your motors a bit on the powerfull side, mine are actually small servo motors and push the model at scale speed plus a bit. Yours have the potential to be a bit over the top so I would experiment with the voltages and hence battery pack configurations before committing to them. You may find that six volts will be plenty so maybe a 4 x "C" cell pack might give you a decent life plus a suitable voltage to prevent excessive speeds.
I would have a good play around in the bath er sorry test tank, before going much further!