It won't help with the MDL prepayment - but have you considered the "rib sharing" options that are out there (if you plan to be out there every weekend in all weathers - then maybe irrelevant, but I am guessing with a wife and two kids one of the reasons for selling the big boat is it just isn't getting used enough at the moment).
There are a couple of trade members on here who run rib sharing schemes: scm
who runs Lynx Rib Club
- which operates Scorpions. The club owns the boats and in effect you are just paying a share of the running costs / depreciation. You might get a much better RIB this way than you would with a 10k budget - which if you are used to big boat "finishing" might be better. RIBshare
of the same name operates Cobra ribs, on a similar basis.
And then there is RIBshack
who I don't think? are members here but operate a different model - where you own a share of the boat, but they manage it all for you. That way you feel as though your cash investment (less than the 10k you were talking about) is not completely wasted - but your operating costs are reduced also.
There are other companies running similar approaches too which googling or searching here will uncover.