Well my first thought is that she's just so unlucky with the timing.
Every factor in the equation is against her.
I do feel the frustrations. I've had my share on my wife's own immigration journey.
Concerning your above idea. You need to read the regulation very carefully.
The rule states:-
Means if you post it on the 24th, 25th, 26th or 27th then the postmark is the date of application and her passport will show she was not physically present in UK on the needed day. Yes, it's a real so-and-so but I can't advise you do that. As UKBA themselves warn, that is the major cause of refusal. So they WILL do it.If you send your application form and application fee by post, the date of application is the date of posting. This is decided by the postmark. If the postmark is illegible or missing, the date of postage is taken as being at least 1 day before it is received by us.
Because the 28th is on a Monday (the day of new rules implementation) it's not even possible to use a special hand delivery courier service.
I'm sorry to be the bearer of this but you're going to need to resolve the issue of which English Test and which Test Centre and when to do it.
Personally I think if your wife has been in UK for 3 years she will absolutely sail through the required tests without any problem.
Despite the fact that many test providers do insist on all 4 elements (Reading, Writing, Speaking and Listening) the UKBA are only concerned with Speaking and Listening.
(read the UKBA news iten again)
Even your wife will fail writing and reading elements will make no difference just as long as she makes the pass mark at Speaking and Listening.
Please do take a look at the IELTS test centre link I provided in post #11 and check out those 62 UK centres. Maybe there's one within reasonable access.
Keep us informed on how you and your wife will proceed. It may well help many others who will follow you.