Good luck with your project; please keep us posted as to your progress!
For all sorts of RV related components, check out two RV surplus dealers located in White Pigeon, MI; Johnson Supply and Bontragers (maybe Bontreagers). I think they both have web sites for more information. I purchased all my windows from them for $20 each brand new. Last time I was touring these two places I saw some slide outs sitting around ready to be grabbed!
Hope this helps.
Speed Gray, K8SG
Grand Rapids, MI
Highway OPie (Speed Gray) Grand Rapids, MI: 2003 Peterbilt 379 Motorhome; 550 hp 6NZ Caterpillar C15, Eaton-Fuller 18 speed transmission, 3.36 rear; 63" sleeper and 16' Morgan box.(email@example.com). There are many Peterbilts, but this one is mine!