I wouldn't say it's an alternative, because CJDNS and I2P operate at different levels of the stack. In other words, you could theoretically run I2P on top of CJDNS. I like the project very much, though integration into Nightweb isn't likely because it requires the creation of a TUN device, which is a kernel-level facility and thus requires root permissions.
From Responsive Design[1] to jQuery Mobile[2] you really have a lot of options. Depending on your wants/needs you will find that each has its own benefits and downfalls.
There was also a good discussion recently about Responsive Design[3]