If you are not opposed to a dell this is what I use on my laptop
http://accessories.us.dell.com/sna/productdetail.aspx?c=us&l=en&s=bsd&cs=04&sku=430-3115
Gives me a real serial port, parallel port, ps2 and a couple of extra USB ports
I am not opposed to Dells, per se, they just don't stand up... the problem is we want something more durable...
Elitebooks are metal, water "resistant" (we have spilled coffee, soda, etc. and had other mild wet conditions with no issues). Technicians are tough on laptops, Elitebooks stand up well and we have easily destroyed Latitudes in just a year or so.
Actually looks like we are going with the Elitebook 850 G1's, Discrete Graphics, Win 7 Pro 64-bit, Core i7, 16GB RAM, 500GB SSD drives, docking stations, and the Edgeport/1 adapters. IT department is trying to think more for the future I guess, just got the email that they ordered 3 to start with and if all goes well, it will become the standard.