Timbutdim,
A current SPA ME IR is only required to start your first Multi Crew Type.
If you already hold a Multi Pilot Rating even if it is no longer current then you are able to undertake a second rating without renewing; as a multi crew IR is type specific then once the the rating is complete then you are issued a "new rating" with it your multi pilot IR privileges are renewed.
Remember your MPA IR will not at present give any single pilot IR privileges.
North of the Field;
Correct Air Taxi work; JAR Ops requirement is 700 hours total time minumum which must also include 40 hours p1 multi IFR.
Insurance requirements may require more (typical 1000 hours total, 200 multi), that said a couple of companies have a concession to allow pilots with 400 hours total time (and this must include the 40 p1 multi IFR) to fly single pilot (believe Centreline Air Charter have this concession and Ravenair).
Bizjets: again as I mentioned it will be insurance requirements driving the hours requirement of crews; the punters in the back will have no idea what hours or experience of the crews up front will be.
N of the F, the only thing I can recommend as it is obvious at the moment neither a SSTR or an FI rating is available to you; would be if you are doing some SEP hire, make sure everytime you fly that you land away some where and use it as an opportunity to hand out some CVs to GA operators; you may strike lucky and get either some safety pilot work (as some one mentioned) or some kind of aerial work. There really is nothing else you can do until your finances improve and allow you to consider the other options.