Need to make a library of mammalian coding sequences
Verify where these transcripts are generally present (this should not be difficult for common organisms)
If they are all expressed in a certain tissue use cDNA from that tissue
If not then pool the cDNAs from different tissues such that all genes can be amplified
cDNA libraries (including whole organism) are also available and you may obtain them from the nearest repository (I guess NCBI also provides).


Some other things you can do:


Ask the primer synthesis company to provide primer sets it in a
96well format.
DNA synthesis is also a decent option (it takes something like $0.5 
per base pair), but that can be expensive if your cDNAs are huge.