Go to eBay and type in "morse decoder" and you'll see a bunch of options. I don't know how reliable the Chicom stuff is and I won't buy it, but it's there. I have a Japanese made GHD decoder I use for monitoring my straight key code and it seems to be very accurate unless my speed varies too much but it was about $180. It shows 26 characters - enough to show the entire alphabet or a string of text without having to look up each time I key a word. It's really helped my accuracy. MFJ sells one as well.
Oh, I saw an ad yesterday for a used "Morserino 32" on QRZ - look that one up. It has a bunch of training features, but the one I liked was a feature that you have to key in what the unit sends you and it tells you whether you got it right or not. I thought that would be cool, but someone snapped it up while I was researching it and they're out of stock.
Good luck and congrats on the copying - that's my weakest area.