For all-biz-class, depending upon when it's needed, MaxJet's all-business-class 767-200 might be available. http://www.maxjet.com/flyingMaxjetCharterContent.do
They're an advertiser on a.net and their VP/Planning reads a.net and posts here. Their a/c is in JFK at one end of its London turns. They do indeed do charter.
Also, a couple of all-biz-class 717s from Midwest Express might also suit your needs, but you would need more than one plane. I would definitely call them as well as MaxJet.
The obvious candidate is North American, as noted above, but here are some ideas:
North American Airlines www.flynaa.com
Scheduled-service carrier based at JFK
as noted above flying 752s and 763s. They did Bush's campaign plane with significant biz seating, as well as Club Med charters for decades. Picked up a lot of the vacation charter business of the former TransMeridien Airlines. Its parent, World Air Holdings, has another carrier, World Airways, that has a fleet of 14 MD11s and 3 DC10s and which runs a VIP-configuration MD11 back and forth to Angola from Houston several times a week as a private charter by the US-Africa Energy Association for the airline subsidiary of the Angolan state-owned oil company.
ATA Airlines, Inc. www.ata.com
Scheduled service carrier and big charter operator based at IND
flies 752s, 753s, 738s and 733s. Used to have an all-first-class L1011, believe it or not, that saw some corporate and incentive charter use.
Miami Air www.miamiair.com
Flies 738s and 727s. Specializes in one-time, incentive, ad hoc (e.g. college football teams etc) and track charter. Respected operator, rumoured to have unbelievably good food, although the carriers above also know how to lay out a spread, too. Miami, FL
Ryan International Airlines www.flyryan.com
Does a lot of tour group track charter and military charter with 737s and 757s. Wichita, KS
Omni Air International, 757s and DC10s. www.omniairintl.com
Does a lot of military charter and some vacation package charter. Tulsa, OK
USA3000 Airlines www.usa3000.com
Sked-service and track charter operator, which is owned by the Apple Vacations people and gets most of their track charter business.
[Edited 2006-10-10 22:59:52]