Square flap #10 Envelopes?

[xcelprint]

Hey, does anyone have a good quality #10 with square flap for use in digital press? I don't run enough envelopes to warrant a digital envelope press but I would like to print 500 or 1000 when needed on my Xerox 700. The envelopes I stock are diagonal flap and even with flaps extended I can't get the envelope to pass all the way thru the machine. I think a square flap would make it work.

What brand do you suggest?

Thanks.

Robert