We had so many "Failed Fosterers" LOL (foster carers who decided to Adopt their Foster Kitty), that we at KumfyKatz Rescue are running a "Try before you Adopt" scheme.
We supply everything to start off a Potential Fosterer including a 24/7 support helpline, thanks to Sponsorship from a couple of local (to us) Companies, and help from the RMP's at Aldershot. We cover all costs (vets bills, food, litter, beds, scratchers, litter trays & scoops, cleaning materials, toys etc). We haven't excluded anyone who would like to Foster a cat for us: Service families, single people, the retired -- anyone can foster short or long term, once homechecked, vet checked and LA checked..
The scheme has been running now for just over two months, and I have to say that apart from a few teething problems at the beginning, it's proving to be relatively successful. 9 cats have found permanent forever homes this way, and 6 more in Foster. Of the 9 homed, 8 were fostered for up to a fortnight, then the Foster Carers decided they had "fallen in love with Darling..." and wanted to adopt. 3 of those Foster Carers have also offered to Foster again.
We also have (Thanks in the main to Rushmoor Voluntary Services) a couple of entries of the doit.org website, where potential volunteers go to look for voluntary work in their areas. We've only done the entry in the last week, and had two potential Fosterers call already.
We put a little poster for our "TRY BEFORE YOU ADOPT" scheme everywhere we could think of where people sit or stand and wait for something (Doctors, Library, Schools, Day Care Centres, Services Welfare Offices waiting rooms, vets, local Cafes, Pubs, and Bus Stops etc. Even got some of local Cabbies (Bless them all) to put a small postcard-sized notice in the back of their cabs, and local Snack Wagons have one too. Also did a leaflet drop at a couple of local car boot sales and fetes.
We have at this very moment 84 pending Pre-Fostering Homechecks to do in this area (and if anyone would like to help (must have experience, car and phone)......) So potentially, we have spaces for 84+ cats! Yikes!
Maybe you could try something similar in your area?
Best to get some sort of sponsorship first, talk to local businesses (bigger ones), work up a good relationship with them, talk to your local RVS centres, talk to your vets, and other vets in your area.
Prepare for the influx! (We didn't, fully, that's why we had teething problems from the start).
Best of luck!