My suggestion, contact someone like Sunny Communications (they specialized in refurbished radios). See if they can help you out. If not, use them to keep you running on a budget.
I had a customer last year who made the decision that they wanted to migrate off their private VHF trunking system to a regional 800 MHz system. They had begun purchasing new APX7x000s and a new APX8500 before they decided they didn't have the budget for a full fork lift of new radios. So they concentrated their budget on upgrading from the XTL5000 based consolettes connected to their MCC5500 to APX8500 consolettes (which would give them dual band functionality without having to purchase additional consolettes). To round off the migration they would essentially trade in their other Astro 25 radios to Sunny for 800 MHz versions at $150 delta per radio. Grand total was somewhere around $65,000 (including labor). Our MR was pissed that they went and bought used radios but we happily did the labor.
The year before, this customer's neighbor had made the same migration (off the VHF system to 800 MHz). They were sold APX8x00s. 32 mobiles and 80 portables plus a new MCC7100 console (literally the last one Motorola shipped) with APX6500 consolettes. What they had was a mix of XTS1500's and XTL1500's. They were sold on the 8k's "for interoperability". To be fair, they did need a new console but they did not need the 8ks. In fact, once the cutover was finished (which it took me 2 hrs per vehicle to convert dash mount XTLs in GamberJohson consoles) to the remote mount 8500's on 32 vehicles) the radio's never went back to VHF. Two years later less than 5 SU's have had any operation on VHF and it certainly wasn't anything that couldn't be handled over a temporary patch. All together that one cost them something like $650,000.
My real point, given adequate notice I've yet to meet a small agency (even volunteer) which could not budget a radio upgrade. Unfortunately you were thrown in to a situation where your predecessor (or lack of) didn't pay attention and plan ahead and now you are having to deal with it. It's not just a Motorola thing though. I've had Kenwood tell customers with 5 year old radios that they needed to buy new radios too...so there's that.