Some guns I have sold off are just a fond memory. Others have left a void that begged and nagged and grated until I finally ran out and bought another. I have done this a few times with 10/22s thinking that I had done it all and that there would be nothing to gain from further tinkering. Well.... I was wrong. The 10/22 has too many incarnations to let it slip out of your life. Always keep at least one. You can always shuffle parts around to change it if the mood strikes you and when that crazy new part or conversion kit come along you can spring for it.
The can be a bit of a small money hole, but I think that it is more than offset by the cost of your standard .22lr ammo.
I fond that there is nothing so captivating or modification hungry than in the centre fire market. Maybe the M14, but you are going to be shelling out more than tripple the money to get the same results there.
I would advise that if you are really happy with the 10/22, to keep it. You will likely miss it and what you get to replace it may not give you the same happiness the 10/22 did, and even if it does, it will probably cost you more.