There are several "plug and play" nano's on the market, dennerle do a good one, and so do superfish, but what i would do is see if you can find the tank size you want, just the glass, and then decide on lighting, there are some good clip on lights or luiminares for 1 foot tanks that can be found on ebay, aswell as a 45cm arcadia one, next it would be best to decide on what type of setup and how techy you want to take it, for example i have brought pressurised co2 for my nano, and for me its worth it, but i can understand that in a desk situation there might not be much room for things like that, so you could alternatively look at easycarbo or ae carbon. also another thing is filtration, is there no room for an external, you can get hobs or small internals in the "plug and play" sets.