If this were the case it would have been done already. That would also involve the EU either effectively giving up its own rules or implementing internal border controls to the point of selling the Republic of Ireland up the creek (a deal that can get vetoed by any of the EU27 countries, and no prizes for guessing who'd be first to veto that arrangement).
This guy sums up the Brexit situation quite well. I don't think he's ever voted if you're worried about hidden agendas.
And this explanatory note of his explains why none of the EU's pre-existing relationships have been able to act as a precedent.
To have access to the common market the EU has four freedoms that are non-negotiable: freedom of movement of people, goods, services and capital. Access to the common market (the second biggest economy in the world btw. It'll still be far bigger than China without the UK) involves accepting the EU's rules on those four freedoms and several other things. The only way for the UK to have its cake and eat it too would be for the EU to blink. I don't have up-to-date numbers, but if memory serves trade to the UK represents something like 8% of the EU's exports, while trade in the opposite direction is about 45% of the UK's trade. Both sides come out worse off without a deal (I'd also argue they both come out worse off WITH a deal too), but the EU's so rigid it wouldn't even blink if it had the most to lose. The EU's not being a "bully" as you said before, it's just enforcing its own rules.
The Leave campaign strongly implied (if not outright stated) that the UK would be able to strike a deal that provides access to the common market while also controlling their own immigration policy (not accepting the EU's rules on the free movement of people) and the like. And the impunity with which they were able to lie like that actually really annoys me.
Fwiw there actually is a deal that's already been struck, which may well have the numbers to pass if the Tories get their majority. In terms of the trilemma outlined above it basically means putting a border through the Irish sea and providing a huge amount of administrative and legal complexities at the British end.
https://www.bbc.com/news/uk-50083026
It looks like there's actually a majority in Northern Ireland that's in favour of splitting off from the UK and reunifying with the Republic, which would only grow over time given the demographics of the stay/reunify backers. And that says nothing of Scotland, which backed Remain by something like 60-40 and in its own independence referendum decided to stay on the UK on the promise it would stay in the EU. I don't think the Leave vote would have won had the break-up of the UK been tabled as a possibility.
The EU is incredibly protectionist and for all the good it does there's a lot of ridiculous stuff thrown in, but my thesis has always been that the UK won't get a better deal out of the EU than what it had as a member.
As difficult a task as it sounds, it's actually monumentally worse. Every law the UK passed since joining the EU has been treated as being in accordance with the EU, and treating EU law as its own law. This includes precedents from European courts applying to UK courts as well as legislation itself. Scotland's constitution also states that non-EU law is "no law" (ie, not recognised at home). Basically, every single law since the 1970s will have to be rewritten.
But from an NZ perspective our government's one of the best in the world at striking trade deals that don't sell our country up the river (due in no small part to a similar economic trauma in the 1980s), so we won't complain about another willing trade partner with a lot of history and similarities. And it means we'd have another strong partner in trying to lobby the US to finally stop neglecting the WTO.
