I have a mid 2011 27" iMac; the problem is that I got a work laptop (Dell Lattitude E7440) and annoyingly I can't connect my laptop to the MAC display. There are a few software options that could make this work but the laptop is so locked down that I won't be able to amend the local firewall in anyway so none have worked.

I have given up trying to find software or ways of connecting my laptop to the Mac, just seems it can't be done. I am now left to buy another monitor, and this is where I could do with some advise - the Monitor will need to be both:

1 - not look too out of place next to a 27" iMac. Same size screen would be nice.
2 - when its not connected it could be used as a dual screen for the iMac (bit of a long shot request)

Any available options out there?