I have tried Alvyn, it doesn't appear to be updated since 2004.
Alvyn was meant to be an AMOSPro-compatible BASIC interpreter, and captures much of the feel of the AMOSPro editor. While the Alvyn editor was written in Java, it appears the Alvyn interpreter is written in C++, while jAMAL is written entirely in Java, so merging the two projects would require a rewrite of one or both (and a merging of sprite/screen engines, etc). This may be more fruitful when jAMAL is more complete and memory-efficient.
In addition to Alvyn, there was also the Mattathias BASIC
project, which is written in ANSI C and aims to implement a full BASIC compiler compatible with AMOSPro (unlike Alvyn which is interpreted). This was discussed over at AMOS Factory
(and I enquired here
about the possibility of combining code with jAMAL), unfortunately it appears Mattathias is no longer in active development either.
These 3 projects all attempt a high-level reimplementation of parts of AMOSPro on modern hardware and operating systems. This is a similar approach AROS has taken with AmigaOS, and is a similar kind of reimplementation to projects such as ScummVM (and even Wine, as it implements the API level) - only allowing many enhancements beyond the capabilities of the original Amiga.
This is in contrast to emulators such as WinUAE, which replicate vintage hardware at a very low level, and so can already run the original AMOSPro near-perfectly under emulation - albeit limited to the original chipset's graphics. This is the approach taken by the AMOS for Windows installer
P.S. A few years ago, I wrote a simple BASIC-style interpreter in C++ called "MequaScript", itself much inspired by AMOS.
If I ever get the time to do a Java port (it would need a lot of work and expanding), I would consider integrating AMOSPro-compatible syntax, and finally merging it with the jAMAL project. (Not this year however, unfortunately.)