Take a look at TM's network load balancing feature, available on all our internetwork products.  It is capable of balancing VPN traffic across two or more paths, with automatic management of link path failures and resumptions.  For many small office locations, it is difficult to cost justify a T-1.  Many of our customers will load balance across two lower-cost business-class DSL connections.  We have a few installed sites that load balance across a wire-line technology like T-1 or DSL and a wireless link from a WISP.  With Titanium Mirror products, you have the flexibility to load-balance across two or more links of the type that best fit your specific cost/risk/reliability situation.