My friend threw me a surprise one when I was pregnant with dd it was lovely. We played funny games, did a sweepstake to guess sex and weight of baby and the person who got it right got the money (after birth obviously)
There were mocktails and snacks. My friends brought gifts many of which were for me not the baby :O
I think it's considered bad form to throw your own and write lists of demands gifts but loads of people do so why not :O
I really hope someone is throwing me another surprise one this time round!
Serious answer: you never host your own shower - that's a job for sister or BF. You do not have a list. The hostess does however do some co-ordination amongst guests to avoid duplicates. It is for first baby only.
Feel free to ignore any or all of the above. Many people do.
Parties to celebrate an impending new arrival do not have to be called "showers" - perhaps the solution for you is to give it a different name and free yourself from the expectations of a traditional shower?
Could you just send out your bank details and ask for people to transfer money in. You wouldn't need to have them round then. Perhaps they could give you £25 if they come to your baby shower and have to endure enforced fun and £50 if they are allowed to avoid it.