That's a decent sized burden to be dragging around behind you when you're trying to get cash flow built up. You can actually have 2 PayPal accounts, one business and one private, but in your case they would both be linked to ebay and therefore, both subject to the same hold, so that won't work.
Short of them lifting your limit, and to be honest I wouldn't waste my time with emails trying to get that done. I would be calling them and talking to someone in person. I've always had far more success, and quicker success, when dealing with them on the phone rather than through email.
Should that attempt still fail, you can look at adding alternative payment options. Offer EFT, now most people will still prefer to use PayPal because of the safety aspect, however you can try to coax them to EFT by offering a cheaper price and faster shipping for direct deposits on your items. Maybe a discount off a multiple item purchase or even a 5% discount off their next purchase and so on.
You'll more than likely need to get a little creative, but you have to give them a reason to use the EFT payment option over PayPal with an incentive or two, without making it look too obvious that you are trying too hard to keep them away from the PayPal option or they can then get suspicious and you can lose the sale altogether.
Your best solution, call PayPal!