I recently bought a caldene tweed jacket - it fits like a glove however I'm the opposite to you (short) but managed to fit into a childs size, the womens were longer so prob worth having a look. Not cheap tho about £200 for ladies (£150 for childs) - the perks for being a short arse!!! http://www.derbyhouse.co.uk/prodshow.asp?id=3099&cat=148&scats=148#
I have an Alexander James jacket...got it measured for me so fits an absolute treat. Excellent quality and you can pick all your material, buttons, velvet bits etc. pretty reasonably priced too considering!
I have a lovely Mears tweed jacket, but Caldene are nice as well (they have some really lovely materials).
I originally went to Alexander James stand (at Bramham) thinking I would treat myself, but the young guy there was an absolute a**e and not interested in making a sale at all, so ended up with my off the peg Mears (which is just as nice and I'm sure a fraction of the price).
If you are tall and if you can track one down the equetech ones are really great. No use for a short arse but if you are tall they are very smart and large made all over. In fact you may need a smaller size than usual. best to check measurements before you buy.