No.  Order Type is not customizable.  You can create multiple Accounts Receivable Accounts by having different customer divisions.  Each division can post to it's own AR GL Account.  Then Customers in Division 00- can post to one account and customers in Divison 01- can post to a different division.  If you don't use divisions now, and you turn it on, it can't be turned off later.  Maybe test this is a backup company first to confirm this is what yoou want.  

If you are using the Job Cost module, the retention feature is part of that module and will allow you to specify the GL account for the retention receivable account.  You will not need to set up multiple customer numbers.  

Dang, thank you for the response.

We do not use the Job Costing module unfortunately.

I have seen this done before. Get with a master developer such as DSD and ask for a quote.