Believe all AC components on Alpines were supplied by Acme Air--now out of business. Reference other posts on this forum, try ACMEAIRPARTS.com and ask for Richard [also do a forum search on dash AC or heater core]. They have most of the inventory and intellectual property from Acme Air. Believe one of the compressors used was a Tama brand. Or, just take the OEM compressor to any large Auto AC distributor and I am sure they can match one up for you--specific compressor brand/model shouldn't matter.
2003 40' MDTS
Garden Ridge, Texas