A floating Reamer Holder is not impossible to make. At the Spalding M E Show the other year, there were two displayed. One was mine on the Peterborough stand and the other was, from memory on the Stamford standard.
The one on the Stamford stand used parallel OD, with internal Morse taper, sleeves, whereas mine is based on a Morse taper arbor carrying a body to take a loose fitting (shop made) ER25 collet holder. The collet nut was purchased from Arc Euro Trade, (much too complicated and accurate for me to make, anyway) This holds Hand Reamers. For Machine Reamers, I made up a larger body to take shop made ER 32 collets with 1,2, and 3 MT internal tapers. (Left soft in view of the likely very limited use)
As usual, no drawings, but if you send me a PM with your E mail address, I'll take pictures and send to you.
The only bits that may be considered complicated are cutting the 16 degree included internal taper, and the 32 x 1.5mm external thread. The ER32 collets with the internal MT tapers were a bit more of a challenge.
Howard