You might want to explore with her activities at school or in the community that would allow her to pursue her interests in more depth. Science fairs are excellent venues for allowing children to work on a creative project over a period of time. Local colleges or universities may offer Saturday programs in subjects like architecture, math, or science that are activity-based. Similarly, science centers or museums often support creative activities of this sort.
Another avenue you might pursue is finding a mentor for your daughter. A local engineer or other technically-oriented professional might be able to provide some opportunities for your daughter to shadow that person in his/her inventive activities.
The National Association for Gifted Children offers a publication, "Parenting for High Potential," specifically aimed at parents. NAGC also has a special division focused on the topic of creativity.
Two books I would recommend for your daughter are The Kids' Invention Book by Arlene Erlbach and Inventors and Inventions (Grades 4-8) by Lorraine Egan.
Finally, encourage her interest in inventing. When you think of all the wonderful tools we have today -- from computers to Post-It notes to telescoping poles used to help us short people unscrew light bulbs in the ceiling -- they all came from the mind of an inventor.