FCC ticket machines can't issue them I don't think (I think they said on their online forum that it was something they were looking at) and I am sure FCC is no different to most other TOCs around the country, so the big problem is getting a ticket in advance - as you need to plan ahead, especially if ordering online.
If you simply buy the ticket the night before, that's fine as long as you go to the station when the ticket office is open. But, of course, there's always the question: how do you get to the station to buy the ticket if you're after a combined bus/rail ticket (suggesting you'd need to go by bus to the station to buy one) and you weren't there anyway? Fine for regular commuters that get a ticket on their way home, but otherwise it's going to cost you more anyway.
Buses will never issue rail tickets, but I wonder if the solution is to sell you a special 'bus to train' ticket that can be used as a voucher when you arrive at the station to take off the price of your plusbus rail ticket? The bus company gets its 'share' from having issued that ticket, so presumably they're happy. The next time you use the bus, you'll need to have converted it to the full rail ticket.
Now, the problem I foresee is if you need more than one bus to get to the station. Second bus can't accept your voucher, as it may otherwise be a cheap way of getting a bus 'season' ticket. The solution there is to make it possible to use two buses for a single fare within an area.. but it could get a bit more complicated.
But, at the end of the day, SOMETHING must be done as the point of plusbus is to offer free bus travel to/from the station (if you have to buy a single ticket on top, I'd very much doubt you would save money at all - just get a normal return if your bus company sells them). At the moment it's really only useful for people that have a season (as I do) or want the bus portion only at their destination station.
