A Ping Anser I bought off eBay had been hacked down to 33".
I find it a little short, so how does one extend a shaft? There are butt extensions on gamola but not sure how one would work and how easy it would be.
For putters a butt extension of any length is fine as you do not subject the putter to the same forces (ie. a full swing) as regular clubs. Extending it will change the "swingweight" of the putter and may feel different to you - however, all of this is of little or no consequence if you now have a putter that allows you to:
Be comfortable and cause no pain during putting practice sessions
Position your eyes directly over the ball
Sole the putter so that neither the toe or the heel are sticking up in the air
Allow you to grip the putter without any tension due to elbows being bent
Promote a relaxed, natural, unforced stroke
You can buy extensions, or take it to a good club fitter who should be able to save the grip for you, reshaft with an extender of some sorts. Usually you use steel in steel, and plastic/wood in graphite. A lot of clubfitters will also use homespun extenders fashioned out of discarded shafts which if done properly is perfectly fine. The key with installing an extender is in the preparation if it is not to come loose, ie. the extender has to be prepped and so does the shaft it is going into.
After removing the grip (there are ways to remove and re-use a putter grip. But maybe think about replacing the grip too), you insert the 'waffled' end of the extender into the shaft. The idea is that the waffled end is sanded down to be a tight fit inside the shaft, and that you use some epoxy to fix the extender in place. If the extender is a good tight fit, no need for the epoxy on a putter (tho' I would recommend epoxy on other clubs because you are swinging them with considerable force).
Then cut the protruding end of the extender to give your finished club length. A basic hackswa will go through the plastic in seconds. Remember that the butt-end of the grip will add about 0.25" to the length of the club.