Any steel frame bike should work. As to parking if it is a an office park you work at I bet if you got a cheaper regular bike and just U locked the wheel to the frame, took the seat post with you and left the rest near the rear entrance (so as not to cause any complaints from building management), it would not be stolen.
2000 Montague CX, I do not recommend it, but still ride it.
Strida 3, I recommend it for rides < 10mi wo steep hills.
2006 Rowbike 720 Sport, I recommend it as an exercise bike.
1996 Birdy, Recommend.
Wieleder CARiBIKE (folding), decent frame.