I give a few bonuses, I give the rep's $50 for opening a new account. If that customer spends over $2,500 in the first 6 months, they get another $50. At the end of the year I give them a $2,500 bonus for every $1 million in sales, with no cap.
We use an accounting system called Apparel Magic, it is designed for the apparel industry, we've had it modified in a few places to fit our needs. It's rather pricey (STARTING price is $5,000 for a single user copy) took some (ok, a lot of) getting used to, but its great, and it runs on MAC!
It keeps track of payments, billing, has manufacturing modules build in, tracks sales, royalties, you can set user info to give you sales team access to inventory and orders, but not let them see your account balances, on and on. It almost does too much!
As far as deals gone bad ... This depends on a lot of things.
The rep's commission is recorded when the order ships. So, if we get a bad check, we eat it, the rep still gets paid. Its not technically their fault a customer can't pay. We'll often times ask the reps to go visit a bad customer and ask what the deal is? Although, we take no crap from bad check-er's I'm an !@#$% when it comes to billing. At 30 days you get a statement, 60 you get a phone call, 90 you get a certified letter, 120 we go to court. I will get my money
Occasionally, we get a deal that just seems "fishy" in general, if we have a bad feeling about a new customer placing large orders out of the gate, we ask for either a 50% deposit, or a credit card. Most don't squabble, and if they do, there's usually a reason.
We generally don't take commissions away from reps at all, the ONLY exception is if a rep takes an order and just plain screws it up. Like if the rep quotes/writes an order for Ladies jackets, and then enters it into the system as Mens jackets. Then yes, they will get their commission taken away, because it was their mistake. Now, if WE (office / art / production) screw up, say it was supposed to be Navy on Ash, and we sew Ash on Navy (did that last week) we pay anyway, even if the customer cancels. Its not fair to the rep in Minnesota, that the warehouse in Massachusetts screwed up.
Hope I didn't ramble on too much.
Let me know if you have any other questions.
I would love to know how it works in the screenprint world, someday I would love to have a setup for screenprinting. Right now I job it out to a friend, it works well, we throw each other jobs, but he sometimes he's a little slow on large orders.