The video below shows a number of ways to attach differently shaped routers.
Unfortunately, these models were discontinued and are disappearing from retailers, though they are still available on EBay. Their newer replacements will also work, though the mounting system shown next will be different.
Rotating the base can eliminate the need for a bracket that accommodates the position of the base's screw hole.
To rotate the trim router's base, remove the four screws from the base as shown in the drawing. Rotate the base so the cord and switch point in the desired direction, and so the 1/4 inch bolt hole in the router’s base faces the spindle plate.
Reinstall and tighten the four screws.
Do not pull downward on the base, or the commutator will be pulled from the brushes. Should this happen, the top can be removed to access the brush assembly.
One mount uses the base of a muffler clamp with plumber's pipe hanger. The other is a shop-cut wooden cradle with a band clamp.
Another option is a custom CNC cut cradle as shown here.
This was made by Nick for his 25x25 as shown on the gallery page.
It has received good reviews, and is one of the quieter full sized routers.
The same motor body assembly of this router is available with different base and handle configurations. Only the motor body is used on the CNC machines.
Though the machines will not be able to push this router to its stalling point, it can still be handy to use because of its longer life and its larger collet capacity as compared to trim routers.
Cradles with band clamps can tie this router to the axis.
It is also safer since it is unnecessary to chase a variable speed router's control dial around the table.These controls are available from woodworking stores and Harbor Freight; prices start around $20.