Here is my Orion ED80 f7.5 (fl=600mm) Refractor, shown here on the Losmondy G-11 mount. Also an ST-80 guide scope which I picked up secondhand.
The ED80 has become incredibly popular at only 400 here in the UK, a quarter of the price you'd expect to pay for the APO performance it delivers.
Click here for the Cloudy Nights review of the ED80.  
I can swap the guide scope between the SN10 and this ED80 in a few minutes.
This setup is particularly stable on the excellent Losmondy G-11 mount which can take loads up to 60lbs. I only have to use the small 11lb counterweight. I don't have a counterweight light enough to balance the ED80 on its own!