I can work precisely to your requirements and may suggest you any existing component/plugin available in market and customize it without changing the actual code, so you can upgrade it anytime
Either you purchase a readymade extension or a plugin for your existing site, you cannot be 100% satisfied. The purchased product will always need some customisation, to tift your need, be it Joomla’s Extensions like Lovefactory , RSForms, Community Builder, Fabrik etc or be it WordPress’s plugins like Woocommerce etc. I do it all, without modifying the original code.