false hems for sleeve lengthening

That's a lot of fabric to ask for in order to lengthen the sleeve. Most ready to wear jackets do have have that much.

Your best bet might be to go Made to Measure, as obviously the RTW jackets do not fit you at all.

I've had this done several times due to long arms. For years I would buy longs so that the sleeves would be long enough. After I realized regulars fit better, I had tailors add material to the lining in the sleeve so that the sleeves could be let out to the fullest extent. It worked well.

dont know of any rtw that has enough inside the sleeve to lengthen 3"
if its suit sleeves then there is the cut off form the cuffs. that can be used to face the inside of the sleeve. usually the most can be 2" or a little less.

Methuselah thread revival!

Has anyone had jacket sleeves lengthened via the insertion of a false hem? How did it work out? I note that many alterations services list this as something they can do on their websites, so it can't be that hard...

this is a common occurrence. most sleeves have a max of 2 " at the bottom. a 1/4" is needed to sew the extra cloth added to the bottom, that leaves 1 and 3/4 of cloth to add to the length. and yes the added cloth comes from the trouser cut off, if there is any.
the tailor may also need to add some sleeve lining also.
every one should ask the tailor to return the trouser cut off. it always comes handy. after all you paid for it, its yours.

I've had a tailor use the additional material from my pants to create lining for my sleeves.

I've actually let the sleeves out on two of my jackets. A huge pain in the ass, and very time consuming. However, I always added a different material to the lining, not to the jacket. That would have been a lot easier. All that being said, there is usually 2" available like mentioned above.

Thanks for these comments everyone, very helpful. Sounds like this is entirely do-able.