From RFC 1213 you could try sysDescr(1.3.6.1.2.1.1.1 ):
sysDescr
"A textual description of the entity. This value should include the full name and version identification of the system's hardware type, software operating-system, and networking software. It is mandatory that this only contain printable ASCII characters."
The system section of 1213 has other interesting pieces of data like this too, like the sysObjectID (1.3.6.1.2.1.1.2.0):
sysObjectID
DESCRIPTION
The vendor's authoritative identification of the network management subsystem contained in the entity. This value is allocated within the SMI enterprises subtree (1.3.6.1.4.1) and provides an easy and unambiguous means for determining "what kind of box" is being managed. For example, if vendor "Flintstones, Inc." was assigned the subtree 1.3.6.1.4.1.4242, it could assign the identifier 1.3.6.1.4.1.4242.1.1 to its `Fred Router'."