PS Aeroproducts stock Brodak tanks and some of their own:
http://www.psaeroproducts.org
I suspect the engine is slap back against the leading edge so the tank will need to be in the wing - or you can get away with it on the pod on the opposite side to the engine.
PAW do tanks too - as well as 2.5cc diesels:
http://www.eifflaender.com/modeller.htm
And Hallam Models too:
Hallam Models - Control line models, trainers and combat kits. Mail order only. SAE for details.
69, Bole Hill Lane,
Sheffield,
England.
S10 1 SA
Tel: 01142 665624
Best to ring as they don't always have tanks available.
Tony
For Nostalgias sake you could also peek at my site:
http://www.the.elmores.btinternet.co.uk/telmore.html