Neither kit was particularly 'limited', if my memory is correct the TSR2 ran to some 15,000 units on first release and the Nimrod was about 20,000. I couldn't quote you a figure for the Stratos 4 TSR2 re-issue. They were not done with cheaper moulds, that is just another alternative fact pedalled by the rumour factory. The TSR2 was 'sold' - mistakenly in my view - as a limited edition. The Nimrod production run was based on orders received from wholesalers/retailers. It has to be said that both kits created something of a debacle instigated by the previous Airfix management. In answer to the OP's question, I would think the Valiant will be released at some time in the future, when it's ascertained that there is sufficient demand. The tooling represents a considerable investment and not doing any further production runs doesn't make economic sense. I'd never measure demand by inflated ebay prices, that is usually a sign of blatant profiteering when something is perceived to be in short supply. I saw Valiants for sale on traders stalls at model shows last year, although I can't recall if there were any at Bovington last weekend. There's still some out there.