If you are using stripboard or similar rather than it having to fit an existing PCB / socket, you can get a much larger RAM ICs from RS at around the same price:
I've managed to find plenty of LS00's, 21's and 153's, as well as a tube of SOP surface mount Hitachi HM62256ALFP-10T SRAM chips in my stock. The only ones I haven't managed to find yet are the LS08's, and I know I must have some around somewhere. You might be able to use the SRAM's with an adaptor board. Let me know if your interested in the parts, and I'll get some off to you if I can get your address, but it may be next week sometime.