Have you considered a Multico Tenoner? They sell for around the £1,200 mark, take up about the same floor space as a bandsaw and are simply brilliant for producing tennons, offset tennons, scribed tennons, double tennons etc etc, accurately and repeatable. For the money you are suggesting you should be able to get a very clean well setup machine with modern blocks that will take profile cutters as well as disposable rebate blades this makes Producing doors and windows easy.
A slightly larger option is a Secgwick tennoner, the preference is one with three heads. Most feel that the main advantages over the multico are
1. The moving table is larger with simpler clamping for more industrial use. The fence also can be canted to produced angled tennons easily.
2. The multico has each cutter block independently adjusted, the Sedgwick you set the thickness of the tennon with and then adjust both blocks to place the tennon where you want it.
3. The sedgwick takes 60mm thick blocks where as the Multico are 50mm. The third block is extremely useful.
4. The Sedgwick (later machines) have compliant guarding the Mutico's needs a little adapting.
I have a Multico machine.