your problem is you are a bit short , but it is possible to lower every bike by a few inches , its easy done , wont cost a fortune
the main problem is there are not many singles produced nowadays , ok some trailies but for people like me who dont like the traillie style ....
so i stick with the 150cc-250cc bikes and my next will be from china , the only marketsegment
where singles are the norm and they are getting better, best in the moment are bikes from zongsheng , they also produce now for piaggio italy , means they produce parts for all kind of motorcycles from italy which belong to the piaggio group (aprilia,motoguzzi,laverda,gilera,the spanish company derbi)and they even have a deal with honda
example my honda cbf 250 at zongheng they produce a similar sporty looking bike with basically a copy of my engine but only 230cc
only difference the chinese bikes has 2 bhp more has a larger tank 20 liters, has a nice half fairing and a nicer exhaust sound
twin dic front single disc rear and ABS it only cost half the price somtimes even less
http://www.zongshenamerica.com/products.php?type=Motorcycles&id=001