i know what you mean, i've regretted selling lots of bikes in the past, i find it a wrench to let them go - strange how we get so attached to a piece of metal ,but on the flip side the way i see it is we're only here once and its good to try as many bikes as possible before we peg it!
Line them up in one final photoshoot, pat them on the bottom and once they leave the premises just wait for that increased bank statement balance.....happy days as you've owned & ridden them. There's always another one round the corner waiting to be plucked from the classifieds.