I have always thought the same thing... an old cheap late 90's hyundai excel heater core/fan/motor modded to bolt in a 1600, they work really well, never had problems, should be pretty cheap now 2nd hand. and they're cable.
if you can find something that tucks up under the dash, behind the original 1600 heater trim, clean, hidden, nice.
Pics of the excel unit?
I've always planned on fitting a better setup to mine, but everything I've looked at is mounted width-ways along the passenger side firewall and wouldn't translate well to being orientated length ways in the middle. I also have a few structural differences to work around too, but always come to the conclusion that I will need to fab my own shroud around a retrofitted heater core and a/c core - and who knows what fan will end up being used.