It's a tricky one. the bandit riding position is not that different from the RF600, which has far far higher bars than you'd think. I'd suggest going to somewhere like the Ace cafe or a local biker meet, and asking people if you can sit on as many different bikes as possible. I'm sure most people will be happy to oblige if you explain the situation, as many bikers are always happy to encourage more people onto two wheels. If budget is a little restricted how about a Kawasaki Zephyr 550? not the fastest or best finished bike, but the engine (a development of the Z550 and GPz 550) is incredibly reliable and feels very nice to use, and the bike does look good. Parts are cheap and available and common to many other Kawasakis. Is there a specific reason for an unfaired bike? the faired road biased bikes like the RF600, Thunder Cat, GSX600F, early CBR600F and ZZR 600 are actually much better to ride than nakeds, as the weight distribution and fairing offer a far less tiring ride. wind blast becomes a real issue after an hour or so on a naked bike, and the arse biased weight distribution that feels better standing still doesn't work anything like as well on the move. the most uncomfortable bike I ever rode was a Jinlun cruiser, because you either rode it upright with the bars in your lap, or leaning back hanging off the bars which was absolute torture after about 15 mins. Suzuki are really good at making unpopular middleweight bikes that are actually very good. The GSX teapot was never popular because of its looks (I fail to see what's so bad personally) ditto the RF600 - both are excellent bikes. The type of owners that have them don't tend to be too harsh on them either, so a lot of good examples remain. Steel frames are the way forward on the road because if you do drop it you are far less likely to bend or crack the frame. My mate has been using a 97 R reg RF600 to commute between Milton Keynes and Hinkley - about 500 miles a week since September last year, weather permitting. The three owner 8000 mile from new bike cost him £1050 last year, has had no significant issues and still looks and sounds very fresh. An excellent bike - its VERY hard to find a reason why you would need more for a few years after passing your test. I've ridden the bike many times, and its really an awful lot of very competent bike for the money. The reality is that now with just shy of 17,000 miles on the clock its still a low mileage tidy bike in good order, and if he were to sell it now he'd get pretty much every penny back. Its very hard to argue a deal like that.
The bikes you mention phil are really quite old and there won't be many even decent ones of them left - the Zephyr is a courier special after all. For my money I'd get a Kawasaki ER-6 or ER-5, or the Honda CB500
My lad passed his test and rides a 620 Multistrada as his first big bike. Had to have it restricted to 33BHP (he is 18)
I see he mentioned wanting naked because he wanted a more upright riding position, well the CBF600 has a half fairing and is quite upright. I had one and it was great, it was my first " modern " bike when I returned to biking, handled well, was comfortable, and is really a far less radical version of the CBR. As also mentioned above a visit to a local meet and ask folks there if you can try sitting on their bikes to get an idea of what might suit. It's how my missus chose the 600 Monster she has as being the one for her.
upright bikes can cause problems for some lower back conditions, and also can cause numb bum syndrome quicker than a moderately canted riding position. the most comfortable bike I have ever ridden was my old CBR600FL - after a 280 mile ride I felt like I had only just got on the bike. The VFR 750 has similar ergonomics, but will be too quick and heavy for a novice.
