The association I train with was started up by Andre Noquet, who reached 8th dan in aikido.
he trained in Judo for many years, heard about O'sensei and went to train with him. he became Uchi deshi and trained under O'sensei for a long time. (cant remember how long
he returned to france and found his judoka friends thought he had gone soft, as many of the principles that he had been taught changed his perspective of life. They soon learned differently. I didnt go back to judo.
The, now, head of our association started in judo also. I think he switched to aikido after may years, met Master Noquet and trained under him. he never went back to judo either.
there are alot of people that have done it (it just so happens that two of the people who made the switch are people that I have a great deal of respect for). and i am sure that the switch has gone the other way
but, saying all of this... other people I know that have switched from judo to aikido, their main reason for changing is judo related injury that they do not think will be aggrivated by aikido. usually their knees
main thing is, judo will help your aikido ukemi, which is initially one of the most difficult things for a begginer to learn I have found.
you have that right and your aikido is great fun as you can really experience the techniques early on
enough babble from me