interesting setup, your furnace not gas force air? why you need an air handler while can you adapt to furnace?
of course your technician wants to sale you a new unit...lol only money talks, everything else walks..
anyway, I am pretty sure you can find a air handler fits in your space, or worst case you can find a multiposition furnace, only use its blower to push cold air.
this is pic of a hard start kit, most HVAC place sells them, $15.