Sounds like a workable plan, here a few things to consider;
A large router suitable for table use will normally come with both half inch and quarter inch collets, and for most you can get an 8mm collet as well. These are the most common sizes for router cutter shafts and there are plenty of cutters available in all three sizes.
A large router will weigh in excess of 6Kg so your table needs to be able to support that sort of weight without sagging (if the top sags in the middle it will make it almost impossible to carry out any accurate work).
One option would be to use a commercial router insert plate set into an offcut of kitchen work top (I suggest at least 19mm thick). This gives a strong stable work surface which, due to the laminate, is also fairly slippery making it easy to use.
Trend sell a router insert plate which would suite your T5 and, later on, any other large router. You just drill suitable mounting holes into the insert using the router base plate as a guide.
See this link for details -
http://www.trend-uk.com/en/UK/product/RTI_PLATE/6/insert plate/router_table_insert_plate_.html
One possible problem with this plate is that it is nearly 10mm thick so you would loose 10mm from the depth of cut, not a problem with a large router that has a generous plunge capacity (typically 80mm) but something to consider for the T5 which has 50mm plunge capacity.
Another thing to consider is the height of the router underneath the table, which, for a large router may be in excess of 400mm, so when you design your table make sure you leave enough clearance underneath the top for the largest router you may later use.
When using a router in a table you will need a fine height adjuster (it is very difficult to set the height of the cutter accurately without one) so you will have to factor the cost of this into your budget.
Finally think about a No Volt Release (NVR) switch. This is a switch that you put between the router and the mains supply. You leave the router switched on permanently (depending on the router you may need some form of lock for the router switch to keep it in the on position) and turn it off and on via the NVR switch. The NVR will cut out if the mains fails so the router wont start up again of its own accord when the mains comes back. Not essential but a useful safety feature. Available from Trend, Axminster, Rutlands etc.
Hope this helps - Martin.