Putting aside how realistic this may or may not be (let alone aircraft types and numbers), may I pose some other questions?
For Defence (and Govt), what other factors need to be considered? For example:
Infrastructure: Would new hangars be needed (thus more $$$ required) or would the original hangars still suffice (if so what existing squadrons using them would need relocating (42 Sqn?), or would a new, smaller hangar need to be built (more $$$) required to house them (eg presumably 42 Sqn's fleet could move into something smaller? Or share another hangar)?
Would new accommodation blocks would need to be built?
Would new maintenance and support facilities need to be built (or would existing facilities cope)?
Didn't Ohakea have its own ground/primary radar systems pre-2001? If so, weren't they decommissioned at the time meaning new facilities and systems would need to be reinstated?
Is there a need for specialised becons and navigation aids for around the country?
Would additional new T-6 Texan training aircraft be required to cater for the increased pilot training activities? I understand they are stretched training pilots as it is, so how many additional Texans would be required?
What would be the LIFT aircraft trainer and how many would be required? (Presumably similar numbers to the Strikemasters and Macchis)? Interesting that planning is underway for the UK and US LIFT aircraft to be replaced (eg the T-7A is being promoted for the USAF).
Can Ohakea cope with another (potentially) 2 or 3 dozen aircraft, mixing "fast air" in with the slower Texan and Beechcraft trainers roaming the same countryside (or would the Texans/Beechcrafts need to relocate), as well as the other operational squadrons (3 Sqn's helicopters and 5 Sqn's Poseidons in due course). Wasn't this one of the reasons why the Singapore F-15 basing didn't proceed?
If this was all to magically happen, it's almost as if the RNZAF needs another purpose built airbase, particularly as Whenuapai is constrained by urban growth and lack of opportunities to expand or lengthen runways etc?
Or how realistic would it be to move the Texans and B350's to Whenuapai, where the airspace is presumably rather congested with commercial airline (and other private training) operations?
So hypothetically speaking (and if the magic money tree is flowering), would a new airbase replace Whenuapai and if so where would it be situated?
Or would it better to retain Ohakea and Whenuapai as they are with no changes to the fleets, but as per the Singapore basing proposal suggestions, build an airfield at Waiouru for the fast jets only? How practical is Waiouru? Some negatives could be having an active volcano nearby (potentially curtailing flying activities), the extremes in temperatures (from freezing to generally only warm in summer) and perhaps lack of opportunities for employment for spouses?
Sorry, not trying to derail the conversation with nonsensical suggestions (like new airfields), but as these issues were highlighted in the Singapore basing proposal, I don't think there was much in the way of discussion on how to address these sorts of issues!