I made my cubbby box for less than a fiver all i have to do is cover it im thinking shag carpet and it has been adapted for speakers. If your handy with wood i would give that a go.
the area in between the drinks holder and the speakers needs hinging still have to countersink all the screw heads but i left my bit set at work so will do that tomorrow i think its good as it took about an hour from me realising i needed one to actually fitting. Hopefully you will try your self.
this is 1 i knocked up 1 evening
does me only sits in without the seat swob in so best of both worlds , when i need to take the grandson out just pop it out and drop the swab back in .