So occasionally I go and theory-hammer out a list for shiggles. This time I was looking at my 5 Land Raiders. Two are sitting in a box unconstructed, while the other 3 I've used before. I have a Crusader, 2 standard Godhammers, and the 2 awaiting construction are Redeemers. You can field 3 LRs with a Brother-Captain HQ. To get more you need Inquisitors. All you need to do is give a 20 point Inquisitor a 6 point Retinue and you can take a Land Raider. Add two of those to a minimal GK force and you have 5 nicely kitted LRs in 1850.
Of course you can get silly and go for 7 LRs or change out PAGKs for ISTs and get more Mech out there. I pointed up 7 LRs with tons of extras added and 4 minimal squads of ISTs in Ordo Malleus Razorbacks and Rhinos for 2500 points.