No way to outsource :( this is already a fulfillment company.
Guys from tech support took that high-performance printer (DA-608) away, promising to bring it back in 10 business days. I definitely love them. Some parts will be shipped either from Japan or may be from other planet and then the Custom and blah-blah-blah...you know.
I imagined myself explaining to my customer that piles of their orders would be delayed for 10 business days because of printing problems. I wonder if they would care :)
So today I bought and tried Canon i850 inkjet. In draft mode it easily prints 20..25 envelopes per minute. As a quick and dirty solution it is perfect. Of course the envelope tray is small. Anyway, I printed about 500 envelopes in less than 30 minutes -- good enough.