I found some limericks on another message board. Some are quite hilarious.
I've posted the British player ones. The ones about Henman are a little harsh. I especially like the Rusedski one:

Andy Murray:

[1] There was a young fellow named Murray
Who aimed for the top in a hurry
He drank more than he ought
Threw up on the court
And then blamed his mum for her curry

[2] British tennis is in for a fright
Cos there's a new star now in sight
With a strain and a tear,
And unfortunate hair,
Young Murray is hitting the heights

Tim Henman

[1] There once was a tennis player called Tim
Who turned up at major champs with a whim
'This is the year that I win
And there will be such a big din
Oops sorry think I'm just being a bit dim'

[2] There was a tennis player named Tim
Whose play was rather thin
He kept saying he could win
What - did he think we were dim?
Or was he talking about his twin?

Greg Rusedski

Said the veteran player Rusedski
I consider Tim Henman quite pesky
He spoiled all my fun
Stopped me being No.1
Still, at least I'm much better than Petchey

Nadal:

There once was a boy called Rafa
who just kept getting sharper and sharper
they said: stick to the clay'
but the boy said 'no way'
for the kid intends to go farther

Roddick:

There is a big server named Andy
He finds all those free points quite handy.
He hits aces for fun,
His forehands like a gun.
But his volley is barely up to club standard.

Sharapova:

The lovely young lass, Sharapova
Came along like a bright supernova
But the Belgians came back
And then Lindsay attacked . . .
Seems her reign at the top is now ova.