thecoreyburton

The video looks good, SuperLumberJack. I'm glad you've solved a lot of your filter problems!

When it comes to game footage, I tend to do three separate encodes and put them all the same MKV video as different selectable streams. This way, I can view the same game in several different ways. I also remove duplicate frames and whatnot, but in this case I'll just elaborate on the resizing:

XBR is good for simple games, such as Super Mario World. It retains a lot of the clarity and smooths a lot of the the round edges without making the image too blurry. It works significantly better than HQX in terms of having a higher resolution, and still functioning in the pre-rendered Donkey Kong Country games. The downside is that still images in those games appear a little watered out, but upon playback the motion looks a little better than before. It's just a shame there's no scale=8.
This is your traditional nearest-neighbor resize. Assuming the output's gonna be YUV, it's nice to keep an even number (I prefer multiples of four) as the resize value, to avoid any chroma bleeding. This gives a pixel-accurate look to how the emulator displays the game and it's a good option if all the other resizing methods don't meet your needs.
If you're looking for the an old TV look, then this is what you'd likely go for. It's very customizable and listed below are simply my own settings. The time it takes is extensive, but I've found the final product to be more than worth it. In addition to simply resizing and filtering spatially, the colors are tweaked by the filter slightly to give a more natural look:
I know I didn't answer your question directly regarding the resizer you wanted, but I'm hoping that if ever you're having trouble deciding what to do this can help a bit. You can easily chuck your final script in the mix and make another encode and compare them. As frustrating as getting the right filter can be, it can open the door to a lot of new things. MKV is a very versatile container and is not limited to a single video stream, so you can always double up if there are two you like. The problem with emulators is that they are giving you a much more clear, digital output than the original console. You're going to have to make a sacrifice one way or another and it just depends on what you're comfortable with. If you're happy with what you've chosen, remember it's all subjective and what's best for you is what's best.

Happy encoding!

Edit: I just noticed you mentioned you're using Fraps for capturing. Whilst FRAPS is a great piece of software I use frequently, try BizHawk from TASVideos. It has the bsnes/higan core build into it for SNES emulation so you won't be compromising and it has a built-in AVI dumping feature- you just tell it to save an AVI, choose a (preferably lossless) codec, and it does! You don't have to worry about cropping or timing or missing certain frames.