Sunitinib Malate With or Without Gemcitabine Hydrochloride in Treating Patients With Advanced Kidney Cancer That Cannot Be Removed By Surgery

Inclusion Criteria: * Histologically confirmed\* renal cell carcinoma of any subtype containing any sarcomatoid features NOTE: \*Patients must have a paraffin-embedded tumor specimen from the kidney or metastatic site available for central review and confirmation of tumor histology * Measurable advanced disease that is not resectable by surgery * Patients with resected or radiated brain metastases or those treated with stereotactic radiation therapy are eligible, provided they have been off steroids for at least 2 weeks * More than 2 weeks since prior radiotherapy and recovered * Previously irradiated lesions must not be the sole site of disease * Eastern Cooperative Oncology Group (ECOG) performance status 0-2 * Absolute neutrophil count (ANC) ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 * Hemoglobin ≥ 9.0 g/dL (transfusions allowed) * Serum creatinine clearance ≥ 30 mL/min * serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) ≤ 2.5 times upper limit of normal (ULN; ≤ 5 times ULN in the presence of liver metastases) * Total bilirubin ≤ 1.5 times ULN * Baseline corrected QT interval \< 500 msec on EKG * Able to swallow pills * Negative pregnancy test * Fertile patients must use effective contraception before and during study treatment * More than 2 weeks since prior and no concurrent ketoconazole, dexamethasone, dysrhythmic drugs (terfenadine, quinidine, procainamide, sotalol, probucol, bepridil, indapamide, or flecainide), halo…