Short answer to your title...NO.
You can look into SCTP: http://en.wikipedia.org/wiki/Stream_Control_Transmission_Protocol
It doesn't (nor does any other protocol) actually aggregate multiple packets within a packet, but it does allow for multiple streams of chunks of data to help with transmission times, although it doesn't really reduce overhead.
Various WAN optimization methods exist to help out with overhead if you mean it in terms of reducing the # or frequency of packet transmissions. Dedupe, compression, caching, multicast, etc. Most WAN optimization/acceleration products use multiple methods like these to "speed up" data transmission. Robust Header Compression and other means of getting rid of the overhead of TCP/IP headers and various SYN/ACK spoofing will cut down on overhead and latency.
You'll have to be more explicit in what you are trying to accomplish though if you want better answers.